I am a Severo Ochoa Postdoctoral Researcher at CREAF, Spain. Using an individual-based approach, I try to understand the role of individual heterogeneity in how animal groups form and function and deal with environmental change. Read more here!

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jollethebiologist

@jollethebiologist

While in the colder winter months most streams look devoid of animal life, if you look closer, you can see that there is often actually still much going on. This shallow refuge pool for example hosts a large number of small invertebrates known as ostracods, actively swimming around like small space ships, fuelled by the warmth of the sun. They are a favorite snack for many fish species, so the fact that they are so plentiful here likely suggests fish did not reach this refuge pool
#riverresearch #freshwaterecology #freshwaterstream #macrophotography #invertebrates #fishfood #naturalrivers #natura_catalunya #riuscatalans #catalunya_natura #aigua

jollethebiologist

•

While in the colder winter months most streams look devoid of animal life, if you look closer, you can see that there is often actually still much going on. This shallow refuge pool for example hosts a large number of small invertebrates known as ostracods, actively swimming around like small space ships, fuelled by the warmth of the sun. They are a favorite snack for many fish species, so the fact that they are so plentiful here likely suggests fish did not reach this refuge pool #riverresearch #freshwaterecology #freshwaterstream #macrophotography #invertebrates #fishfood #naturalrivers #natura_catalunya #riuscatalans #catalunya_natura #aigua

2 days ago

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1/9

For some of my river surveys I snorkel to best monitor the different micro habitats and occurence of fish. Although it may look lush, the water is freezing cold (4-5 °c), and most fish are very inactive and hard to find, hidden deep in the river banks. Some of the stretches I snorkled were only 30-40cm deep but host an amazing varied aquascape of plants, pebbles, leaves and roots. It i's a whole different world that most people never even think about
#riverresearch #riversnorkeling #freshwatersnorkling #fishsurvey #fieldbiology

jollethebiologist

•

For some of my river surveys I snorkel to best monitor the different micro habitats and occurence of fish. Although it may look lush, the water is freezing cold (4-5 °c), and most fish are very inactive and hard to find, hidden deep in the river banks. Some of the stretches I snorkled were only 30-40cm deep but host an amazing varied aquascape of plants, pebbles, leaves and roots. It i's a whole different world that most people never even think about #riverresearch #riversnorkeling #freshwatersnorkling #fishsurvey #fieldbiology

4 days ago

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2/9

Back in the field, this time exploring the Daró, a highly intermittent stream in north-east Catalunya. For large stretches near the city of la Bisbal I found it to be dry, with here and there still a patch of water. But a bit further upstream there are some nice permanent pools such as this one with great underwater refuges for fish
#labisbal #riudaró #gavarres #natura_catalunya #riverresearch #naturalrivers #freshwaterecology #ecology #fieldwork

jollethebiologist

•

Back in the field, this time exploring the Daró, a highly intermittent stream in north-east Catalunya. For large stretches near the city of la Bisbal I found it to be dry, with here and there still a patch of water. But a bit further upstream there are some nice permanent pools such as this one with great underwater refuges for fish #labisbal #riudaró #gavarres #natura_catalunya #riverresearch #naturalrivers #freshwaterecology #ecology #fieldwork

4 days ago

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3/9

Nice to be out in the field again! Spent the day exploring de Orlina in north-eastern Catalunya, a river I had not yet been before. While upstream the water was still flowing, further downstream where the riverbed was wider, the stream was dry and only some refuge pools remained. It has rained very little the last months so am interested to see how connectivity of the river changes after a couple days of rain. Unfortunately I did not see a single fish all day, but it could be some fish were there, hiding deep in the river margins. L'orlina is one of the nicer, still mostly natural, unaffected streams in the area and I found good habitats for three-spined sticklebacks, so am interested to go back soon to do some proper surveys
#fieldwork #freshwater #ecology #freshwaterstream #fieldsurvey #rius #riu #riuscatalans #mediambient #natura #aigua #catalunyaexperience #natura_catalunya #batecrius

jollethebiologist

•

Nice to be out in the field again! Spent the day exploring de Orlina in north-eastern Catalunya, a river I had not yet been before. While upstream the water was still flowing, further downstream where the riverbed was wider, the stream was dry and only some refuge pools remained. It has rained very little the last months so am interested to see how connectivity of the river changes after a couple days of rain. Unfortunately I did not see a single fish all day, but it could be some fish were there, hiding deep in the river margins. L'orlina is one of the nicer, still mostly natural, unaffected streams in the area and I found good habitats for three-spined sticklebacks, so am interested to go back soon to do some proper surveys #fieldwork #freshwater #ecology #freshwaterstream #fieldsurvey #rius #riu #riuscatalans #mediambient #natura #aigua #catalunyaexperience #natura_catalunya #batecrius

1 week ago

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4/9

I am very excited to have finally finished the large testing area of my new Aquatic Movement Lab for controlled laboratory studies of animal behaviour. It is the final component of my lab that I still had to complete. The large enclosed area can be monitored and recorded using the array of calibrated cameras from above. I will use it both to observe the movements of groups of fish in large, heterogeneous arenas (up to 3.5 x 2.5m) as well as to film multiple groups simultaneously in different environments and contexts. In particular, my next experiments will focus on trying to understand how fish, both individually and collectively, deal with the severe environmental changes associated with draught. Excited to get started!
#sciencelab #scienceexperiment #science #scientist #lab #experiment #fishlab #aquaria

jollethebiologist

•

I am very excited to have finally finished the large testing area of my new Aquatic Movement Lab for controlled laboratory studies of animal behaviour. It is the final component of my lab that I still had to complete. The large enclosed area can be monitored and recorded using the array of calibrated cameras from above. I will use it both to observe the movements of groups of fish in large, heterogeneous arenas (up to 3.5 x 2.5m) as well as to film multiple groups simultaneously in different environments and contexts. In particular, my next experiments will focus on trying to understand how fish, both individually and collectively, deal with the severe environmental changes associated with draught. Excited to get started! #sciencelab #scienceexperiment #science #scientist #lab #experiment #fishlab #aquaria

4 weeks ago

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5/9

New preprint out on predation risk in schooling prey!
Predation is one of the main drivers of social grouping in animals. Hence, understanding when, where, and how predators attack animal groups is of fundamental importance. By sophisticated experiments in which we tracked pike hunting free-swimming schools of fish, we not only provide novel insights into predator decision-making, but show the key properties related to both predator and prey that influence individual's risk to be targeted and survive predator attacks.
Our findings will have important consequences for understanding the costs and benefits of animal grouping and thereby the evolution of social and collective behaviour.
Interested to read the paper? You can find more information at jollejolles.com!

jollethebiologist

•

New preprint out on predation risk in schooling prey! Predation is one of the main drivers of social grouping in animals. Hence, understanding when, where, and how predators attack animal groups is of fundamental importance. By sophisticated experiments in which we tracked pike hunting free-swimming schools of fish, we not only provide novel insights into predator decision-making, but show the key properties related to both predator and prey that influence individual's risk to be targeted and survive predator attacks. Our findings will have important consequences for understanding the costs and benefits of animal grouping and thereby the evolution of social and collective behaviour. Interested to read the paper? You can find more information at jollejolles.com!

1 month ago

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6/9

Some more DIY and tinkering in the lab to try out some new ideas 😅, having fun!

jollethebiologist

•

Some more DIY and tinkering in the lab to try out some new ideas 😅, having fun!

2 months ago

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7/9

Working from home, tracking a new dataset and adding some features to my tracking software. Its cold and dark outside and I am pretty chilly sitting still behind my desk all day with ho heating on.. But I must say I like the cold, it makes me really focused. Coding and writing your own software can be quite frustrating at times and sometimes requires considerable trial and error before you find what resultated in that annoying error. But developing my own software with all capabilities that I need really pays of in the long run. Will show some more insights soon!

jollethebiologist

•

Working from home, tracking a new dataset and adding some features to my tracking software. Its cold and dark outside and I am pretty chilly sitting still behind my desk all day with ho heating on.. But I must say I like the cold, it makes me really focused. Coding and writing your own software can be quite frustrating at times and sometimes requires considerable trial and error before you find what resultated in that annoying error. But developing my own software with all capabilities that I need really pays of in the long run. Will show some more insights soon!

2 months ago

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8/9

Sun just came out after some cold and cloudy days 🌤 so had to get some fresh air! I have been working indoors on a grant application the past days ✍🏼 to help fund some exciting field work next summer. Unfortunately applying for funding takes up quite a considerable amount of time for most scientists.. I do see value in writing grants though, even when rejected, as it helps to focus your research and its potential impacts. Rejections - of grants, papers, or positions - are unfortunately something most scientists will have to deal with regularly, irrespective of how good they are, making strong ambition and persistence two key characteristics to make it in academia. Now back to my grant application..!

jollethebiologist

•

Sun just came out after some cold and cloudy days 🌤 so had to get some fresh air! I have been working indoors on a grant application the past days ✍🏼 to help fund some exciting field work next summer. Unfortunately applying for funding takes up quite a considerable amount of time for most scientists.. I do see value in writing grants though, even when rejected, as it helps to focus your research and its potential impacts. Rejections - of grants, papers, or positions - are unfortunately something most scientists will have to deal with regularly, irrespective of how good they are, making strong ambition and persistence two key characteristics to make it in academia. Now back to my grant application..!

2 months ago

View on Instagram |

9/9

Twitter

Jolle W JollesFollow

Severo Ochoa postdoctoral researcher at CREAF, Barcelona, focused on the role of individual heterogeneity in animal groups across social and ecological scales

Retweet on Twitter Jolle W Jolles Retweeted

CollectiveLabs @CollectiveBRL·

22 Dec

Seeing the waves even made old hand Jens Krause standing still for a moment, deeply impressed by nature’s beauty. >900 analyzed bird attacks later, we know the fish do it to confuse the birds. @LeibnizIGB @scioi_cluster @dfg_public https://authors.elsevier.com/c/1eHx-3QW8RwqtZ

Retweet on Twitter Jolle W Jolles Retweeted

Valerio Sbragaglia @ValeSbra·

18 Dec

Finally online! We showed a mechanism through which size-selective mortality can affect shoaling behaviour with consequences for fishing and natural mortality. A nice video representation of the paper is coming...stay tuned. @LeibnizIGB @ICMCSIC https://twitter.com/RArlinghausFish/status/1472205343564480515

Robert Arlinghaus@RArlinghausFish

Our latest paper online @ASNAmNat (superb reviewers and editors) deals with alteration of shoaling due to fishing. Led by @ValeSbra with @PRomanczuk and @PKlamser Happy Christmas https://www.journals.uchicago.edu/doi/10.1086/718591

New video

While snorkelling in the Bodensee, I found a large number of pikes stalking juvenile fish in the reeds along the shores. The pikes here can easily get 1m and are actually quite easy to approach to within 2m when quiet. Beautiful to see these hunters up close in the wild.

See all videos about our work...

the Jolles Lab

From individual to collective behaviour across social and ecological scales

Elected Graduate Research Officer